Characterizing the Rigidly Rotating Magnetosphere Stars HD 345439 and HD 23478

TL;DR

This paper studies two rapidly rotating magnetic stars, HD 345439 and HD 23478, revealing their periodic variability and magnetic confinement effects through multi-wavelength photometric and spectroscopic observations.

Contribution

It provides detailed multi-epoch analysis of these stars, confirming their classification as rigidly rotating magnetosphere stars with a common period.

Findings

Detected a ~0.7701 day period in photometry and spectroscopy.

Observed coherent line profile variability consistent with magnetosphere models.

Confirmed magnetic confinement effects through emission line evolution.

Abstract

The SDSS III APOGEE survey recently identified two new $\sigma$ Ori E type candidates, HD 345439 and HD 23478, which are a rare subset of rapidly rotating massive stars whose large (kGauss) magnetic fields confine circumstellar material around these systems. Our analysis of multi-epoch photometric observations of HD 345439 from the KELT, SuperWASP, and ASAS surveys reveals the presence of a $\sim$0.7701 day period in each dataset, suggesting the system is amongst the faster known $\sigma$ Ori E analogs. We also see clear evidence that the strength of H-alpha, H I Brackett series lines, and He I lines also vary on a $\sim$0.7701 day period from our analysis of multi-epoch, multi-wavelength spectroscopic monitoring of the system from the APO 3.5m telescope. We trace the evolution of select emission line profiles in the system, and observe coherent line profile variability in both optical and infrared H I lines, as expected for rigidly rotating magnetosphere stars. We also analyze the evolution of the H I Br-11 line strength and line profile in multi-epoch observations of HD 23478 from the SDSS-III APOGEE instrument. The observed periodic behavior is consistent with that recently reported by Sikora and collaborators in optical spectra.